Field of the Invention
The present invention relates to wireless communications, and more particularly, to a communication method supporting a plurality of serving cells and an apparatus using the method.
Related Art
The long term evolution (LTE) based on 3rd generation partnership project (3GPP) technical specification (TS) release 8 is widely employed mobile communication standard. Recently, a LTE-advanced (LTE-A) based on 3GPP TS release 10 supporting multiple carriers is under standardization.
In a communication system, a duplex scheme includes a time division duplex (TDD) and a frequency division duplex (FDD). The TDD provides an uplink communication and a downlink communication in the same frequency band. The FDD provides the uplink communication and the downlink communication in different frequency bands.
A user equipment (UE) can support a full duplex or a half-duplex. A full-duplex device supports uplink communication and downlink communication simultaneously. A half-duplex device supports only one of uplink communication and downlink communication at one time.
A carrier aggregation (CA) is a technique capable of providing a plurality of component carriers to the UE. Each component carrier may be defined as one cell. When the plurality of component carriers is configured for the UE, the UE may receive services from a plurality of serving cells.
Each serving cell may be configured with the FDD or the TDD. In a CA environment, the UE may be configured with a plurality of duplex schemes. For example, if two cells are configured for the UE, the cells may be configured as a TDD cell-TDD cell or a TDD cell-FDD cell. Accordingly, a throughput of the UE may be increased in various network environments.
However, since a plurality of duplex schemes is applied to the UE, there may be a problem in an operation for the downlink communication and the uplink communication.